There’s one little detail about the iPhone X that Apple likes to keep quiet: there’s really two different versions of the phone. Apple sourced baseband modems, the parts that deal with cellular connections, from both Intel and Qualcomm. Depending on where you bought your phone and what network you’re on, your iPhone X could have a Qualcomm or Intel modem — and they’re not created equal.
Provisional testing from SpeedSmart, a company that crowdsources speedtests from individual users through an app, shows that there is a small but real difference in speeds between the Intel and Qualcomm versions of the iPhone X, even when they’re on the same network. The catch is that it’s Intel’s modem, which is regarded to be behind Qualcomm’s in many respects, that turns out to be faster.
Before diving into the results, it’s worth keeping two important things in mind. First, these results aren’t conclusive: the data only measures speed, not variables like location, cell signal, or LTE bands, and the sample size is still small, as the phone hasn’t even been out for two weeks yet. The author of the report says that “an admittedly small number of speed tests have been taken with the iPhone X compared to other iPhone models,” so don’t go jumping to any conclusions just yet.
The second thing to remember is that Apple has artificially limited Qualcomm’s modem to reduce any performance differences between the Intel and Qualcomm phones. Although we don’t know the exact details, it appears that Apple disabled certain LTE-Advanced technologies that Qualcomm’s modem supports but Intel’s does not. Given the complexity of modem design, that could have slowed regular LTE performance on Qualcomm’s chip as well.
All that being said, here’s the important numbers: On AT&T and T-Mobile, the two networks that support both the Qualcomm and Intel iPhone X models, the Intel phone was faster. On AT&T, Intel iPhone X averaged 30.13Mbps, while the Qualcomm iPhone X averaged 27.46Mbps. On T-Mobile, the Intel phone averaged 33.34Mbps, and the Qualcomm device averaged 26.54Mbps.
That’s the opposite result to what Cellular Insights found when it tested the Qualcomm and Intel iPhone 7 Plus models last year. That testing investigated how the two phones performed in “sub-optimal” conditions, and found that the Qualcomm iPhone 7 Plus performed significantly better than the Intel device. At first glance, that seems to have been reversed this year.